The recording of phase holograms in electro-optic materials, particularly single crystals of lithium niobate, is known. Recording of phase holograms in lithium niobate crystals is done by generating an interference pattern through interaction between a coherent reference beam and an object beam. The object beam carrier spatial modulation corresponding to the image to be recorded. The light pattern formed by the interference between the object beam and the reference beam causes a change in the index of refraction of the lithium niobate crystal. The resultant refractive index pattern is a three dimensional pattern representative of the object or information recorded. The information can be read out by addressing the crystal with coherent readout light in the direction of the reference beam. This light is phase modulated in accordance with the recorded refractive index pattern and reproduces the object beam by wavefront reconstruction.